| Summary: | 碩士 === 國立臺北科技大學 === 生物科技研究所 === 97 === The topology of Streptomyces genome is different from other bacteria, because it has not only circular plasmid, but also linear chromosome and plasmid. These linear DNA replicons carry covalent-bound terminal proteins ﹝TPs﹞ at their 5’ end of telomeric DNA. Some of the linear plasmids of Streptomyces have ability of conjugation, and sometimes they also promote transfer their linear chromosome into recipient. The current established mechanism of conjugation is mostly based on circular F plasmid in E. coli system, but this cannot be applied to linear plasmid of Streptomyces. The mechanism of conjugal transfer in Streptomyces is not clear, therefore finding the origin of conjugal transfer﹝oriT﹞ in linear plasmids may help to understand this mechanism. By a strategy of homologous recombination that we can generate different recombinant DNA carrying different parts of SLP2 DNA fragment in vivo. Then we tested the transfer ability of this recombinant DNA where SLP2 was present. A truncated SLP2 variant plasmid would be transferred to recipient if it contains oriT of SLP2. By this method, the oriT was narrowed to an internal 2 kb DNA fragment, locating at the coordinate of 17.9~19.9-kb of SLP2.
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